In the last 20 years, techniques for manufacturing Ultra-Large Scale Integrate (ULSI) circuit components have been rapidly developed. The reason why the ULSI circuit components have been rapidly developed is that a variety of semiconductor fabrication devices capable of supporting fabrication techniques requiring the ultimate techniques have already been developed. Plasma chambers from among the above-mentioned semiconductor fabrication devices have been used not only for general etching processes but also for deposition processes, such that their range of applications has rapidly increased.
A plasma chamber is indicative of semiconductor fabrication equipment, which can artificially form plasma in a reaction space, and can perform a variety of processes such as etching and deposition using the formed plasma. The above-mentioned plasma chamber can be classified into Electron Cyclotron Resonance (ECR) sources, Helicon-Wave Excited Plasma (HWEP) sources, Capacitively Coupled Plasma (CCP) sources, and Inductively Coupled Plasma (ICP) sources, etc. Recently, there have been newly proposed Adaptively Plasma Sources (APS) indicative of not only ICP-source characteristics but also CCP-source characteristics at the same time.
When performing an etching process of a semiconductor wafer using the above-mentioned plasma chamber including the above-mentioned plasma sources, a Critical Dimension (CD) occurs in different ways at the center and an edge of the semi-conductor wafer. In this case, the CD is indicative of a difference between a desired etching profile before performing the etching process and an actual etching profile after performing the etching process. The CD occurs in a first case in which less etching is performed, and also occurs in a second case in which over etching is performed. In this way, the different CDs occur at the center and the edge of the semi-conductor wafer, resulting in deterioration of uniformity. The different CDs occur at the center and the edge of the semiconductor wafer due to a variety of reasons, for example, the occurrence of a polymer acting as a by-product generated by an etching process. Typically, a pumping speed of the polymer acting as the by-product is differently generated at the center and the edge of the semiconductor wafer. In more detail, a polymer generated at the edge of the semiconductor wafer has a short moving distance until being pumped, whereas a polymer generated at the center part of the semiconductor wafer has a long moving distance until being pumped. Therefore, over etching occurs at the edge of the semiconductor wafer as compared to the degree of etching at the center part of the semiconductor wafer, such that an etching profile more excessively etched than a desired etching profile occurs. The above-mentioned problem may be encountered in various ways according to whether etching gas capable of generating a relatively large amount of polymer is used or the other etching gas capable of generating a relatively small amount of polymer is used.